The present invention will be described with particular reference to perfume as the benefit agent although the technology is believed applicable to other benefit agents used in surface treatment processes.
In laundry applications deposition of a perfume is used, for example, during fabric treatment processes such as fabric washing and conditioning. Methods of deposition are diverse and include deposition during the wash or rinse stages of the laundry process or direct deposition before or after the wash, such as by spraying or rubbing or by use of impregnated sheets during tumble drying or water additives during steam ironing. The perfume is often incorporated into a carrier or delivery system. Carrier systems for perfumes are typically based on encapsulation or entrapment of the perfume within a matrix.
After deposition onto a surface, a problem exists in that longevity of adherence to that surface of the perfume, in a surfactant containing environment, is inherently poor. A perfume which has been deposited onto a fabric may be washed off again during a main wash, or the perfume may be leached from its carrier into the wash. Protection of the perfume is, therefore, required before and after it has been deposited onto a surface. Much the same problems are encountered with other benefit agents, which are, like perfume typically relatively expensive and present in laundry compositions at relatively low levels.
Similar problems occur in the fields of skin and hair treatment, where perfumes and/or other benefit agents are to be deposited on the skin or the hair.
WO 07/62833 relates to compositions which comprise core-shell encapsulated perfume particles decorated with a polysaccharide which is substantive to cellulose. Preferred polysaccharides disclosed therein are locust bean gum, tamarind xyloglucan, guar gum or mixtures thereof. Thus it is known to have particles comprising a benefit agent (perfume) which use cellulose-substantive polysaccharide as a delivery aid to assist the particles in binding to a specific substrate. The compositions may also comprise one or more enzymes. Suitable enzymes disclosed in the reference include, amongst others, those known as cellulase.
The term cellulase refers to a class of enzymes which show a range of possible reactions on a variety of substrates. One problem with cellulose-substantive polysaccharides is that they have a structure which is generally similar to cellulose, and as such, are subject to attack by “cellulase”.
Similar benefit agent delivery aids have been suggested for polyester, based on phthalate containing polymers similar to so-called soil release polymers. These phthalate polymers are subject to problems of hydrolysis and are not substantive to cotton.
A number of documents disclose that cellulosic materials can also function as soil release polymers and anti-redeposition agents. The use of methyl and ethyl cellulose ethers in detergent compositions is disclosed in U.S. Pat. No. 2,373,863, Vitalis (1945). A great many cellulosics for use in detergents are disclosed in U.S. Pat. No. 2,994,665, Reich, et al. (1961); see also U.S. Pat. No. 3,523,088, Dean, et al. (1970). German Auslegeschrift No. 1,054,638, Van der Werth, Nov. 2, 1956, discloses C12 alkyl benzene sulfonates in combination with carboxylated cellulose derivatives. British Patent No. 1,084,061 discloses low amounts of cellulosics as stabilizers for liquid detergents. British Patent Nos. 927,542; 765,811; and 340,232 also teach cellulosics in detergents.
U.S. Pat. No. 4,174,305 discloses alkyl benzene sulfonate detergent compositions containing cellulose ether soil release agents. U.S. Pat. No. 4,732,639 discloses that some alkyl or alkyl/hydroxy-alkyl cellulose derivatives (with a molar degree of substitution of up to 3.0) are effective as soil release polymers and/or as anti-redeposition polymers. UK 1314897 discloses that hydroxy-propyl methyl cellulose for use as an anti-redeposition and soil release aid, but from that document (as observed in U.S. Pat. No. 6,191,093) it can be seen that performance is somewhat unsatisfactory on pure cotton articles. U.S. Pat. No. 6,200,351 discloses nonionic hydroxy-alkyl cellulose ethers suitable for use as soil release polymers in combination with polyester soil release polymers, which include in particular hydroxy-ethyl, hydroxy-propyl and/or hydroxy-butyl celluloses which may additionally carry alkyl ether groups, more particularly, methyl, ethyl and/or propyl groups.
A need exists for a deposition system which is effective both on cotton and polyester and is stable against hydrolysis and enzyme attack. There is also a need to find effective deposition aids for other substrates.